The present invention broadly relates to a safety device for a fuze of a spinning projectile having an escapement or delay mechanism including a balance wheel.
Generally speaking, the safety device of the present invention is for the fuze of a spinning projectile and comprises an escapement or time delay mechanism having an idle state and an operating state. The escapement mechanism has a balance wheel with a center of gravity and a pivot axis.
A preferred embodiment of the safety device of the present invention is for a spinning projectile having a booster charge and a fuze and defining a projectile axis. The safety device comprises a rotor having a rotor axis radially displaced from the projectile axis and having a safety position and an armed position. The rotor is movable out of the safety position into the armed position when the spinning projectile is fired. The escapement or time delay mechanism cooperates with the rotor and defines means for permitting the rotor to rotate into the armed position after firing of the spinning projectile.
The safety device specifically comprises a first safety element which is responsive to firing forward acceleration and to spin and serves to release the rotor in order to enable it to rotate into the armed or live position, whereas a second safety element, responsive to spin acceleration of the projectile, serves to release the rotor to enable it to rotate the armed or live position.
The safety device is situated in a first housing, i.e. the rotor, the escapement mechanism including the aforementioned second safety element and also the first safety element are located within this first housing and form a unit which can be positioned or inserted between the reinforcement or booster charge and the fuze of the spinning projectile. The first safety element is arranged in a second housing of its own which is installable as an individual unit within the first housing of the safety device.
A known safety device of this general type is disclosed in European Patent No. 0,046,906 wherein there is provided a spin safety element comprising a cylindrical housing in which a spring-loaded insertable piston is located in a bore of the rotor. The piston is displaceable by the projectile spin out of the bore of the rotor against the force of the spring. Three recesses for a blocking or safety mechanism are arranged in the piston. The blocking or safety mechanism protrudes or extends from the first recess into a bore of the cylindrical housing and rests upon a shoulder of the housing of the safety device. The blocking or safety mechanism protrudes or extends from the second recess of the piston only into the bore of the cylindrical housing. In the third recess of the piston the blocking or safety mechanism is located completely in this piston without protruding or extending from this recess.